Electrophotographic photoconductor and aromatic polycarbonate resin for use therein

ABSTRACT

An electrophotographic photoconductor includes an electroconductive support, and a photoconductive layer formed thereon containing as an effective component an aromatic polycarbonate resin having a repeat unit of formula (I), or two repeat units of formulae (II) and (III): ##STR1## wherein Ar 1  to Ar 6 , X, n, k and j are as specified in the specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrophotographic photoconductorcomprising an electroconductive support, and a photoconductive layerformed thereon, comprising an aromatic polycarbonate resin as aneffective component. In addition, the present invention also relates tothe above-mentioned aromatic polycarbonate resin with chargetransporting properties.

2. Discussion of Background

Recently organic photoconductors are used in many copying machines andprinters. These organic photoconductors have a layered structurecomprising a charge generation layer (CGL) and a charge transport layer(CTL) which are successively overlaid on an electroconductive support.The charge transport layer (CTL) is a film-shaped layer comprising abinder resin and a low-molecular-weight charge transport material (CTM)dissolved therein. The addition of such a low-molecular-weight chargetransport material (CTM) to the binder resin lowers the intrinsicmechanical strength of the binder resin, so that the CTL film is fragileand has a low tensile strength. Such lowering of the mechanical strengthof the CTL causes the wearing of the photoconductor or forms scratchesand cracks in the surface of the photoconductor.

Although some vinyl polymers such as polyvinyl anthracene, polyvinylpyrene and poly-N-vinylcarbazole have been studied ashigh-molecular-weight photoconductive materials for forming a chargetransporting complex for use in the conventional organic photoconductor,such polymers are not satisfactory from the viewpoint ofphotosensitivity.

In addition, high-molecular-weight materials having charge transportingproperties have been also studied to eliminate the shortcomings of theabove-mentioned layered photoconductor. For instance, there are proposedan acrylic resin having a triphenylamine structure as reported by M.Stolka et al., in "J. Polym. Sci., vol 21, 969 (1983)"; a vinyl polymerhaving a hydrazone structure as described in "Japan Hard Copy '89 p.67"; and polycarbonate resins having a triarylamine structure asdisclosed in U.S. Pat. Nos. 4,801,517, 4,806,443, 4,806,444, 4,937,165,4,959,288, 5,030,532, 5,034,296, and 5,080,989, and Japanese Laid-OpenPatent Applications Nos. 64-9964, 3-221522, 2-304456, 4-11627, 4-175337,4-18371, 4-31404, and 4-133065. However, any materials have not yet beenput to practical use.

According to the report of "Physical Review B46 6705 (1992)" by M. A.Abkowitz et al., it is confirmed that the drift mobility of ahigh-molecular weight charge transporting material is lower than that ofa low-molecular weight material by one figure. This report is based onthe comparison between the photoconductor comprising a low-molecularweight tetraarylbenzidine derivative dispersed in the photoconductivelayer and the one comprising a high-molecular polycarbonate having atetraarylbenzidine structure in its molecule. The reason for this hasnot been clarified, but it is suggested that the photoconductoremploying the high-molecular weight charge transporting materialproduces poor results in terms of the photosensitivity and the residualpotential although the mechanical strength of the photoconductor isimproved.

Conventionally known representative aromatic polycarbonates are obtainedby allowing 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to asbisphenol A) to react with a carbonate precursor material such asphosgene or diphenylcarbonate. Such polycarbonates made from bisphenol Aare used in many fields because of their excellent characteristics, suchas high transparency, high heat resistance, high dimensional accuracy,and high mechanical strength.

For example, this kind of polycarbonate resin is intensively studied asa binder resin for use in an organic photoconductor in the field ofelectrophotography. A variety of aromatic polycarbonate resins have beenproposed as the binder resins for use in the charge transport layer ofthe layered photoconductor.

As previously mentioned, however, the mechanical strength of theaforementioned aromatic polycarbonate resin is decreased by the additionof the low-molecular-weight charge transporting material in the chargetransport layer of the layered electrophotographic photoconductor.

SUMMARY OF THE INVENTION

It is therefore a first object of the present invention to provide anelectrophotographic photoconductor free from the conventionalshortcomings, which can show high photosensitivity and high durability.

A second object of the present invention is to provide an aromaticpolycarbonate resin that is remarkably useful as a high-molecular-weightcharge transporting material for use in an organic electrophotographicphotoconductor.

The above-mentioned first object of the present invention can beachieved by an electrophotographic photoconductor comprising anelectroconductive support, and a photoconductive layer formed thereoncomprising as an effective component an aromatic polycarbonate resinhaving a repeat unit of formula (I): ##STR2## wherein n is an integer of5 to 5000; Ar¹ and Ar⁵ may be the same or different, and represent abivalent aromatic hydrocarbon group which may have a substituent or abivalent heterocyclic group which may have a substituent; Ar², Ar³, Ar⁴and Ar⁶ each may be the same or different, and represent an aromatichydrocarbon group which may have a substituent, or a heterocyclic groupwhich may have a substituent; and X is a bivalent aliphatic group, abivalent cyclic aliphatic group, or ##STR3## in which R¹ and R² are eachindependently an alkyl group which may have a substituent, an aromatichydrocarbon group which may have a substituent, or a halogen atom; l andm are each independently an integer of 0 to 4; and p is an integer of 0or 1, and when p=1, Y is a straight-chain, branched or cyclic alkylenegroup having 1 to 12 carbon atoms, ##STR4## in which Z is a bivalentaliphatic hydrocarbon group; a is an integer of 0 to 20; b is an integerof 1 to 2000; and R³ and R⁴ are each independently an alkyl group whichmay have a substituent or an aromatic hydrocarbon group which may have asubstituent.

In the above-mentioned electrophotographic photoconductor, both of Ar¹and Ar⁵ may be phenylene group in the repeat unit of formula (I) for usein the aromatic polycarbonate resin.

Further, in the above-mentioned photoconductor, the repeat unit offormula (I) may be represented by the following formula (VI): ##STR5##wherein n, Ar², Ar⁶ and X are the same as those previously defined informula (I); R⁵ and R⁶ are each independently an alkyl group which mayhave a substituent, an aromatic hydrocarbon group which may have asubstituent, or a halogen atom; and r and s are each independently aninteger of 0 to 4.

The first object of the present invention can also be achieved by anelectrophotographic photoconductor comprising an electroconductivesupport, and a photoconductive layer formed thereon comprising as aneffective component an aromatic polycarbonate resin having a repeat unitof formula (II) and a repeat unit of formula (III), with the compositionratio of the repeat unit of formula (II) to the repeat unit of formula(III) being in the relationship of 0<k/(k+j)≦1: ##STR6## wherein k is aninteger of 5 to 5000; j is an integer of 0 to 5000; Ar¹ and Ar⁵ may bethe same or different, and represent a bivalent aromatic hydrocarbongroup which may have a substituent or a bivalent heterocyclic groupwhich may have a substituent; Ar², Ar³, Ar⁴ and Ar⁶ each may be the sameor different, and represent an aromatic hydrocarbon group which may havea substituent, or a heterocyclic group which may have a substituent; andX is a bivalent aliphatic group, a bivalent cyclic aliphatic group, or##STR7## in which R¹ and R² are each independently an alkyl group whichmay have a substituent, an aromatic hydrocarbon group which may have asubstituent, or a halogen atom; l and m are each independently aninteger of 0 to 4; and p is an integer of 0 or 1, and when p=1, Y is astraight-chain, branched or cyclic alkylene group having 1 to 12 carbonatoms, ##STR8## in which Z is a bivalent aliphatic hydrocarbon group; ais an integer of 0 to 20; b is an integer of 1 to 2000; and R³ and R⁴are each independently an alkyl group which may have a substituent or anaromatic hydrocarbon group which may have a substituent.

In the above-mentioned electrophotographic photoconductor, both of Ar¹and Ar⁵ may be phenylene group in the repeat unit of formula (II).

Further, in the above-mentioned photoconductor, the repeat unit offormula (II) may be represented by the following formula (VII): ##STR9##wherein k, Ar² and Ar⁶ are the same as those previously defined informula (II); R⁵ and R⁶ are each independently an alkyl group which mayhave a substituent, an aromatic hydrocarbon group which may have asubstituent, or a halogen atom; and r and s are each independently aninteger of 0 to 4.

The second object of the present invention can be achieved by anaromatic polycarbonate resin having a repeat unit of formula (I):##STR10## wherein n is an integer of 5 to 5000; Ar¹ and Ar⁵ may be thesame or different, and represent a bivalent aromatic hydrocarbon groupwhich may have a substituent or a bivalent heterocyclic group which mayhave a substituent; Ar², Ar³, Ar⁴ and Ar⁶ each may be the same ordifferent, and represent an aromatic hydrocarbon group which may have asubstituent, or a heterocyclic group which may have a substituent; and Xis a bivalent aliphatic group, a bivalent cyclic aliphatic group, or##STR11## in which R¹ and R² are each independently an alkyl group whichmay have a substituent, an aromatic hydrocarbon group which may have asubstituent, or a halogen atom; l and m are each independently aninteger of 0 to 4; and p is an integer of 0 or 1, and when p=1, Y is astraight-chain, branched or cyclic alkylene group having 1 to 12 carbonatoms, ##STR12## in which Z is a bivalent aliphatic hydrocarbon group; ais an integer of 0 to 20; b is an integer of 1 to 2000; and R³ and R⁴are each independently an alkyl group which may have a substituent or anaromatic hydrocarbon group which may have a substituent.

In the above-mentioned aromatic polycarbonate resin, both of Ar¹ and Ar⁵may be phenylene group in the repeat unit of formula (I).

Further, in the above-mentioned aromatic polycarbonate resin, the repeatunit of formula (I) may be represented by the following formula (VI):##STR13## wherein n, Ar², Ar⁶ and X are the same as those previouslydefined in formula (I); R⁵ and R⁶ are each independently an alkyl groupwhich may have a substituent, an aromatic hydrocarbon group which mayhave a substituent, or a halogen atom; and r and s are eachindependently an integer of 0 to 4.

The second object of the present invention can also be achieved by anaromatic polycarbonate resin having a repeat unit of formula (II) and arepeat unit of formula (III), with the composition ratio of the repeatunit of formula (II) to the repeat unit of formula (III) being in therelationship of 0<k/(k+j)≦1: ##STR14## wherein k is an integer of 5 to5000; j is an integer of 0 to 5000; Ar¹ and Ar⁵ may be the same ordifferent, and represent a bivalent aromatic hydrocarbon group which mayhave a substituent or a bivalent heterocyclic group which may have asubstituent; Ar², Ar³ ₁ Ar⁴ and Ar⁶ each may be the same or different,and represent an aromatic hydrocarbon group which may have asubstituent, or a heterocyclic group which may have a substituent; and Xis a bivalent aliphatic group, a bivalent cyclic aliphatic group, or##STR15## in which R¹ and R² are each independently an alkyl group whichmay have a substituent, an aromatic hydrocarbon group which may have asubstituent, or a halogen atom; l and m are each independently aninteger of 0 to 4; and p is an integer of 0 to 1, and when p=1, Y is astraight-chain, branched or cyclic alkylene group having 1 to 12 carbonatoms, ##STR16## in which Z is a bivalent aliphatic hydrocarbon group; ais an integer of 0 to 20; b is an integer of 1 to 2000; and R³ and R⁴are each independently an alkyl group which may have a substituent or anaromatic hydrocarbon group which may have a substituent.

In the above-mentioned aromatic polycarbonate resin, both of Ar¹ and Ar⁵may be phenylene group in the repeat unit of formula (II).

Further, in the above-mentioned aromatic polycarbonate resin, the repeatunit of formula (II) may be represented by the following formula (VII):##STR17## wherein k, Ar² and Ar⁶ are the same as those previouslydefined in formula (II); R⁵ and R⁶ are each independently an alkyl groupwhich may have a substituent, an aromatic hydrocarbon group which mayhave a substituent, or a halogen atom; and r and s are eachindependently an integer of 0 to 4.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic cross-sectional view of a first example of anelectrophotographic photoconductor according to the present invention.

FIG. 2 is a schematic cross-sectional view of a second example of anelectrophotographic photoconductor according to the present invention.

FIG. 3 is a schematic cross-sectional view of a third example of anelectrophotographic photoconductor according to the present invention.

FIG. 4 is a schematic cross-sectional view of a fourth example of anelectrophotographic photoconductor according to the present invention.

FIG. 5 is a schematic cross-sectional view of a fifth example of anelectrophotographic photoconductor according to the present invention.

FIG. 6 is a schematic cross-sectional view of a sixth example of anelectrophotographic photoconductor according to the present invention.

FIGS. 7 through 23 are IR spectra of aromatic polycarbonate resinsrespectively synthesized in Examples 1--1 to 1-17 according to thepresent invention, taken by use of an NaCl film.

FIG. 24 is an IR spectrum of a distyrylbenzene compound for thepreparation of a dihydroxyl-group-containing diamine compound No. 1obtained in Preparation Example 1, taken by use of a KBr tablet.

FIG. 25 is an IR spectrum of a dihydroxyl-group-containing diaminecompound No. 1 obtained in Preparation Example 1, taken by use of a KBrtablet.

FIG. 26 is an IR spectrum of a dihydroxyl-group-containing diaminecompound No. 2 obtained in Preparation Example 2.

FIG. 27 is an IR spectrum of a dihydroxyl-group-containing diaminecompound No. 3 obtained in Preparation Example 3.

FIG. 28 is an IR spectrum of a distyrylbenzene compound for thepreparation of a dihydroxyl-group-containing diamine compound No. 4obtained in Preparation Example 4.

FIG. 29 is an IR spectrum of a dihydroxyl-group-containing diaminecompound No. 4 obtained in Preparation Example 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The electrophotographic photoconductor according to the presentinvention comprises a photoconductive layer comprising (i) an aromaticpolycarbonate resin having a repeat unit with a tertiary amino group,represented by formula (I), or (ii) an aromatic polycarbonate resinhaving a repeat unit with a tertiary amino group, represented by formula(II) and a repeat unit of formula (III). Those aromatic polycarbonateresins, which are novel compounds, have charge transporting propertiesand high mechanical strength, so that the photoconductor of the presentinvention can exhibit high photosensitivity and excellent durability.

Further, it is preferable that both of Ar¹ and Ar⁵ be phenylene group inthe repeat unit of formula (I), which is represented by the followingformula (IV): ##STR18## wherein n, Ar² to Ar⁴ and Ar⁶, and X are thesame as those previously defined in formula (I).

It is also preferable that the repeat unit of formula (I) be representedby the following formula (VI): ##STR19## wherein n, Ar² to Ar⁴ and Ar⁶,and X are the same as those previously defined in formula (I); R⁵ and R⁶are each independently and alkyl group which may have a substituent, anaromatic hydrocarbon group which may have a substituent, or a halogenatom; and r and s are each independently an interger of 0 to 4.

In addition, it is preferable that both of Ar¹ and Ar⁵ be phenylenegroup in the repeat unit of formula (II), which is represented by thefollowing formula (V): ##STR20## wherein k, Ar² to Ar⁴ and Ar⁶ are thesame as those previously defined in formula (II).

It is also preferable that the repeat unit of formula (II) berepresented by the following formula (VII): ##STR21## wherein k, Ar² andAr⁶ are the same as those previously defined in formula (II); R⁵ and R⁶are each independently an alkyl group which may have a substituent, anaromatic hydrocarbon group which may have a substituent, or a halogenatom; and r and s are each independently an integer of 0 to 4.

Those aromatic polycarbonate resins according to the present inventioncan be obtained by the method of synthesizing a conventionalpolycarbonate resin, that is, polymerization of a bisphenol and acarbonic acid derivative.

To be more specific, the aromatic polycarbonate resin comprising therepeat unit of formula (II), (V) or (VII) of the present invention canbe produced by the ester interchange between a diol compound having atertiary amino group represented by the following formula (VIII), (IX)or (X) and a bisarylcarbonate compound, or by the polymerization of thediol compound of formula (VIII), (IX) or (X) with phosgene in accordancewith solution polymerization or interfacial polymerization: ##STR22##wherein Ar¹ to Ar⁶, R⁵, R⁶, r, s and X are the same as those previouslydefined in formulae (I) and (VI).

When a diol compound of the following formula (XI) is employed incombination with the diol compound of formula (VIII), (IX) or (X) in thecourse of the polymerization with the phosgene, there can be obtainedthe aromatic polycarbonate resin of the present invention comprising therepeat unit of formula (II) having a tertiary amino group and the repeatunit of formula (III), or the aromatic polycarbonate resin of thepresent invention comprising the repeat unit of formula (V) having atertiary amino group and the repeat unit of formula (III), or thearomatic polycarbonate resin of the present invention comprising therepeat unit of formula (VII) having a tertiary amino group and therepeat unit of formula (III):

    OH--X--OH                                                  (XI)

wherein X is the same as that previously defined in formula (III).

By such a synthesis method, the aromatic polycarbonate resin providedwith the desired characteristics can be obtained. Further, thecomposition ratio of the repeat unit of formula (II) to the repeat unitof formula (III), or that of the repeat unit of formula (V) or (VII) tothe repeat unit of formula (III) can be selected within a wide range inlight of the desired characteristics of the obtained aromaticpolycarbonate resin.

The aromatic polycarbonate resin of the present invention comprising therepeat unit of formula (I), (IV) or (VI) having a tertiary amino groupcan be obtained by polymerizing the diol compound of formula (VIII),(IX) or (X) having a tertiary amino group with a bischloroformatecompound derived from the diol compound of formula (XI) in accordancewith solution polymerization or interfacial polymerization.Alternatively, the above-mentioned aromatic polycarbonate resin can alsobe obtained by polymerizing a bischloroformate derived from the diolcompound of formula (VIII), (IX) or (X) having a tertiary amino groupwith the diol compound of formula (XI).

According to the ester interchange method, a diol compound and abisarylcarbonate compound are mixed in the presence of an inert gas, andthe polymerization reaction is generally carried out at temperature inthe range of 120° to 350° C. under reduced pressure. The pressure in thereaction system is stepwise reduced to 1 mmHg or less in order todistill away the phenols generated during the reaction from the reactionsystem. The reaction is commonly terminated in about one to 4 hours.When necessary, a molecular weight modifier and an antioxidant may beadded to the reaction system. As the bisarylcarbonate compound, diphenylcarbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate,di-p-chlorophenyl carbonate and dinaphthyl carbonate can be employed.

The polymerization of a diol compound with the phosgene is commonlycarried out in the presence of an agent for deacidifying and a solvent.In this case, hydroxides of alkali metals such as sodium hydroxide andpotassium hydroxide, and pyridine can be used as the deacidifying agentsin the above reaction. As the solvent, halogenated hydrocarbon solventssuch as dichloromethane and chlorobenzene can be employed. In addition,a catalyst such as tertiary amine or a quaternary ammonium salt may beused to accelerate the reaction speed. Furthermore, it is also desirableto use phenol or p-tert-butylphenol as a molecular weight modifier. Thepolymerization reaction is generally carried out at temperature in therange of 0° to 40° C. In this case, the polymerization is terminated inseveral minutes to 5 hours. It is desirable to maintain the reactionsystem to pH 10 or more.

In the case of the polymerization of a diol compound with abischloroformate compound, the diol is dissolved in a proper solvent toprepare a solution of the diol compound, and a deacidifying agent andthe bischloroformate compound are added to the above prepared diolsolution. In this case, tertiary amine compounds such as trimethylamine,triethylamine and tripropylamine, and pyridine can be used as thedeacidifying agents. Examples of the solvent for use in theabove-mentioned polymerization reaction are halogenated hydrocarbonsolvents such as dichloromethane, dichloroethane, trichloroethane,tetrachloroethane, trichloroethylene, and chloroform; and cyclic etherssuch as tetrahydrofuran and dioxane. In addition, it is desirable to usephenol or p-tert-butylphenol as a molecular weight modifier. Thereaction temperature is generally in the range of 0° to 40° C. In thiscase, the polymerization is generally terminated in several minutes to 5hours.

To the aromatic polycarbonate resin produced by the previously mentionedmethods, various additives such as an antioxidant, a light stabilizer, athermal stabilizer, a lubricant and a plasticizer can be added whennecessary.

As previously mentioned, the aromatic polycarbonate resin according tothe present invention is a homopolymer comprising a repeat unit of (II),(V) or (VII), an alternating copolymer comprising the repeat unit offormula (I), (IV) or (VI), or a random copolymer or block copolymercomprising the repeat unit of (II), (V) or (VII) and the repeat unit of(III).

It is preferable that the aromatic polycarbonate resin according to thepresent invention thus obtained have a number-average molecular weightof 1,000 to 1,000,000, more preferably in the range of 5,000 to 500,000when expressed by the styrene-reduced value.

The above-mentioned diol compound having a tertiary amine grouprepresented by the formula (VIII), (IX) or (X), which is an intermediatefor preparation of the aromatic polycarbonate resin according to thepresent invention, will now be explained in detail.

In the present invention, there can be employed adihydroxyl-group-containing diamine compound represented by thefollowing formula (XII), which is a novel compound, as the diol compoundhaving a tertiary amine group: ##STR23## wherein R¹ to R⁶, which may bethe same or different, are each independently an alkyl group which mayhave a substituent, a halogen atom, an aromatic hydrocarbon group whichmay have a substituent, or a heterocyclic group which may have asubstituent; a, c and e are each independently an integer of 0 to 4; andb, d and f are each independently an integer of 0 to 5.

Namely, such a dihydroxyl-group-containing diamine compound can be usedas an intermediate for preparation of the aromatic polycarbonate resinaccording to the present invention.

In the formula (XII), the alkyl group represented by R¹ to R⁶ is astraight-chain or branched alkyl group having 1 to 5 carbon atoms. Theabove alkyl group may have a substituent such as a fluorine atom, cyanogroup, or a phenyl group which may have a substituent selected from thegroup consisting of a halogen atom and an alkyl group having 1 to 5carbon atoms.

Specific examples of the above alkyl group include methyl group, ethylgroup, n-propyl group, i-propyl group, tert-butyl group, sec-butylgroup, n-butyl group, i-butyl group, trifluoromethyl group, 2-cyanoethylgroup, benzyl group, 4-chlorobenzyl group, and 4-methylbenzyl group.

Examples of the aromatic hydrocarbon group represented by R¹ to R⁶ arephenyl group, styryl group, β-phenylstyryl group, biphenylyl group,terphenylyl group, naphthyl group, anthryl group, pyrenyl group,fluorenyl group, 9,9-dimethyl-2-fluorenyl group, azulenyl group,triphenylenyl group, and chrysenyl group. Those aromatic hydrocarbongroups may have a substituent such as a lower alkyl group, a loweralkoxyl group, or a halogen atom.

When any of R¹ to R⁶ represents a halogen atom, fluorine, chlorine,bromine and iodine can be employed.

The dihydroxyl-group-containing diamine compound of formula (XII) can besynthesized by the conventional method in accordance with the reactionschemes shown below.

A corresponding aldehyde compound having an alkoxyl group, representedby formula (XIII), is allowed to react with a correspondingbis(phosphonate) compound of formula (XIV) by the modified Wittigreaction, so that a distyrylbenzene compound of formula (XV) can beobtained.

Furthermore, cleavage of an ether linkage of the alkoxyl group iscarried out in the distyrylbenzene compound of formula (xv), so that adihydroxyl-group-containing diamine compound of formula (XII) can beobtained. ##STR24## wherein R¹ to R⁶, and a to f are the same as thosepreviously defined in formula (XII); and R⁷ and R⁸ are eachindependently a lower alkyl group.

In this case, potassium-t-butoxide, sodium hydroxide, potassiumhydroxide, sodium amide, sodium methylate, and potassium methylate canbe used as the basic catalysts.

Examples of the reaction solvent used in the above-mentioned reactionare methanol, ethanol, isopropanol, butanol, 2-methoxyethanol,1,2-dimethoxyethane, bis(2-methoxyethyl)ether, dioxane, tetrahydrofuran,toluene, xylene, dimethyl sulfoxide, N,N-dimethylformamide,N-methylpyrrolidone and 1,3-dimethyl-2-imidazolidinone. Of thesesolvents, a polar solvent such as N,N-dimethylformamide or dimethylsulfoxide is preferably employed.

The reaction temperature may be determined within a wide range dependingon (1) the stability of the employed solvent with respect to theemployed basic catalyst, (2) the reactivity of the condensed components,and (3) the reactivity of the employed basic catalyst as a condensationagent in the solvent. For instance, when a polar solvent is employed,the reaction temperature is in the range of room temperature to 100° C.,preferably in the range of room temperature to 80° C. The reactiontemperature may be further increased when it is desired to curtail thereaction time, or the activity of a condensation agent to be employed islow.

The cleavage of the ether linkage of the alkoxyl group in thedistyrylbenzene compound of formula (XV) can be carried out by usingsodium thioethoxide or trimethylsilyl iodide.

When the above-mentioned sodium thioethoxide is employed for thecleavage of the ether linkage, a solvent such as N,N-dimethylformamideor triamide of hexamethyl phosphoric acid is preferably employed. Thereaction temperature is in the range of room temperature to 180° C.,preferably in the range of 10° to 150° C. The reaction time varies withthe reactivity of the alkoxyl group, so that the reaction may beterminated in about 20 minutes or it may take 10 hours or more. Thecleavage of the ether linkage can be carried out similarly by usingsodium thiomethoxide instead of sodium thioethoxide.

When trimethylsilyl iodide is employed for the cleavage of the etherlinkage, a solvent such as dichloromethane, chloroform, carbontetrachloride, sulfolane or acetonitrile is preferably employed. Thereaction temperature is in the range of room temperature to 100° C. Instead of trimethylsilyl iodide, trimethylsilyl chloride and sodiumiodide may be employed.

Furthermore, the cleavage of the ether linkage can also be carried outusing a reagent such as hydriodic acid.

The bis(phosphonate) compound of formula (XIV) can be readily producedby allowing a corresponding halogen compound to react with trialkylphosphite under the application of heat thereto without any solvent, orin an organic solvent such as toluene, xylene or N,N-dimethylformamide.

A variety of materials such as a polycarbonate resin, polyester resin,polyurethane resin and epoxy resin can be obtained by deriving from thehydroxyl group of the above-mentioned dihydroxyl-group-containingdiamine compound, so that the dihydroxyl-group-containing diaminecompound is considered to be useful as an intermediate for thepreparation of those materials. In particular, an organic polymer suchas a polycarbonate resin prepared from the above-mentioneddihydroxyl-group-containing diamine compound is useful as the organicphotoconductive material.

The polycarbonate resin according to the present invention will now beexplained in detail.

In formulae (I) and (II), Ar¹ and Ar⁵ are each independently a bivalentgroup of an aromatic hydrocarbon group or a heterocyclic group, aspreviously mentioned.

When Ar¹ and Ar⁵ each represent a bivalent aromatic hydrocarbon group,there can be employed bivalent groups derived from the followingaromatic hydrocarbon groups: benzene, naphthalene, biphenyl terphenyl,pyrene, fluorene, and 9,9-dimethylfluorene.

When Ar¹ and Ar⁵ each represent a bivalent heterocyclic group, there canbe employed bivalent groups derived from the following heterocyclicgroups:

thiophene, benzothiophene, furan, benzofuran and carbazole. Further,there can be employed diphenyl ether group and diphenyl thioether groupin which two aryl groups are bonded via oxygen and sulfur.

The above-mentioned bivalent aromatic hydrocarbon group and heterocyclicgroup may have a substituent such as a halogen atom, an alkyl group, oran alkoxyl group as shown below:

(1) A halogen atom; fluorine atom, chlorine atom and bromine atom.

(2) An alkyl group, preferably a straight chain or branched alkyl grouphaving 1 to 12 carbon atoms, more preferably having 1 to 8 carbon atoms,further preferably having 1 to 4 carbon atoms. The alkyl group may havea substituent such as a fluorine atom, hydroxyl group, cyano group, analkoxyl group having 1 to 4 carbon atoms, or a phenyl group which mayhave a substituent selected from the group consisting of a halogen atom,an alkyl group having 1 to 4 carbon atoms, and an alkoxyl group having 1to 4 carbon atoms.

Specific examples of such an alkyl group are methyl group, ethyl group,n-propyl group, i-propyl group, t-butyl group, s-butyl group, n-butylgroup, i-butyl group, trifluoromethyl group, 2-hydroxyethyl group,2-cyanoethyl group, 2-ethoxyethyl group, 2-methoxyethyl group, benzylgroup, 4-chlorobenzyl group, 4-methylbenzyl group, and 4-methoxybenzylgroup.

(3) An alkoxyl group (--OR⁷) in which R⁷ is the same alkyl group aspreviously defined in (2).

Specific examples of such an alkoxyl group are methoxy group, ethoxygroup, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group,s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, 2-cyanoethoxygroup, benzyloxy group, 4-methylbenzyloxy group, and trifluoromethoxygroup.

In formulae (I), (II), (IV), (V), (VI) and (VII), Ar², Ar³, Ar⁴ and Ar⁶are each an aromatic hydrocarbon group or a heterocyclic group, aspreviously mentioned.

Examples of the aromatic hydrocarbon group represented by Ar², Ar³, Ar⁴and Ar⁶ are phenyl group, naphthyl group, biphenylyl group, terphenylylgroup, pyrenyl group, fluorenyl group, 9,9-dimethyl-2-fluorenyl group,and 5H-dibenzo a,d!cycloheptenyl group.

Examples of the heterocyclic group represented by Ar², Ar³, Ar⁴ and Ar⁶are thienyl group, benzothienyl group, furyl group, benzofuranyl groupand carbazolyl group.

The above-mentioned aromatic hydrocarbon group and heterocyclic groupmay have a substituent such as a halogen atom, an alkyl group, or analkoxyl group. In this case, the same halogen atoms, alkyl groups, andalkoxyl groups as mentioned above can be employed.

R¹ and R² in each formula, and R⁵ and R⁶ in formulae (VI) and (VII) areeach independently an alkyl group which may have a substituent, anaromatic hydrocarbon group which may have a substituent, or a halogenatom. R³ and R⁴ each represent an alkyl group which may have asubstituent, or an aromatic hydrocarbon group which may have asubstituent. When each of R¹ to R⁵ represents an aromatic hydrocarbongroup, a substituted or unsubstituted phenyl group or a substituted orunsubstituted biphenylyl group can be employed. With respect to thealkyl group and the halogen atom, the same examples as mentioned abovecan be employed.

Examples of the diol compound represented by formula (XI) includealiphatic diols such as 1,3-propanediol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol,2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol,2-ethyl-1,3-propanediol, diethylene glycol, triethylene glycol,polyethylene glycol and polytetramethylene ether glycol; and cyclicaliphatic diols such as 1,4-cyclohexanediol, 1,3-cyclohexanediol andcyclohexane-1,4-dimethanol.

Examples of the diol compound having an aromatic ring are as follows:4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)methane,1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane,2,2-bis(4-hydroxyphenyl)propane,2,2-bis(3-methyl-4-hydroxyphenyl)propane,1,1-bis(4-hydroxyphenyl)cyclohexane,1,1-bis(4-hydroxy-phenyl)cyclopentane,2,2-bis(3-phenyl-4-hydroxyphenyl)propane,2,2-bis(3-isopropyl-4-hydroxyphenyl)propane,2,2-bis(4-hydroxyphenyl)butane,2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane,2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane,4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenyl-sulfoxide,4,4'-dihydroxydiphenylsulfide,3,3'-dimethyl-4,4'-dihydroxydiphenylsulfide,4,4'-dihydroxy-diphenyloxide, 2,2-bis(4-hydroxyphenyl)hexafluoropropane,9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxyphenyl)xanthene,ethylene glycol-bis(4-hydroxybenzoate), diethyleneglycol-bis(4-hydroxybenzoate), triethyleneglycol-bis(4-hydroxybenzoate), 1,3-bis(4-hydroxyphenyl)-tetramethyldisiloxane, and phenol-modified silicone oil.

In the photoconductors according to the present invention, at least oneof the previously mentioned aromatic polycarbonate resins is containedin the photoconductive layers 2, 2a, 2b, 2c, 2d, and 2e. The aromaticpolycarbonate resin can be employed in different ways, for example, asshown in FIGS. 1 through 6.

In the photoconductor as shown in FIG. 1, a photoconductive layer 2 isformed on an electroconductive support 1, which photoconductive layer 2comprises an aromatic polycarbonate resin of the present invention and asensitizing dye, with the addition thereto of a binder agent (binderresin) when necessary. In this photoconductor, the aromaticpolycarbonate resin works as a photoconductive material, through whichcharge carriers which are necessary for the light decay of thephotoconductor are generated and transported. However, the aromaticpolycarbonate resin itself scarcely absorbs light in the visible lightrange and, therefore, it is necessary to add a sensitizing dye whichabsorbs light in the visible light range in order to form latentelectrostatic images by use of visible light.

Referring to FIG. 2, there is shown an enlarged cross-sectional view ofanother embodiment of an electrophotographic photoconductor according tothe present invention. In this photoconductor, there is formed aphotoconductive layer 2a on an electroconductive support 1. Thephotoconductive layer 2a comprises a charge transport medium 4comprising (i) an aromatic polycarbonate resin of the present invention,optionally in combination with a binder agent, and (ii) a chargegeneration material 3 dispersed in the charge transport medium 4. Inthis embodiment, the aromatic polycarbonate resin (or a mixture of thearomatic polycarbonate resin and the binder agent) constitutes thecharge transport medium 4. The charge generation material 3, which is,for example, an inorganic material or an organic pigment, generatescharge carriers. The charge transport medium 4 accepts the chargecarriers generated by the charge generation material 3 and transportsthose charge carriers.

In this electrophotographic photoconductor, it is basically necessarythat the light-absorption wavelength regions of the charge generationmaterial 3 and the aromatic polycarbonate resin not overlap in thevisible light range. This is because, in order that the chargegeneration material 3 produce charge carriers efficiently, it isnecessary that light pass through the charge transport medium 4 andreach the surface of the charge generation material 3. Since thearomatic polycarbonate resin comprising the repeat unit of formula (I)do not substantially absorb light in the visible range, it can workeffectively as a charge transport material when used with the chargegeneration material 3 which absorbs the light in the visible region andgenerates charge carriers. The charge transport medium 4 may furthercomprise a low-molecular weight charge transport material incombination.

Referring to FIG. 3, there is shown an enlarged cross-sectional view ofa further embodiment of an electrophotographic photoconductor accordingto the present invention. In the figure, there is formed on anelectroconductive support 1 a two-layered photoconductive layer 2bcomprising a charge generation layer 5 containing the charge generationmaterial 3, and a charge transport layer 4 comprising an aromaticpolycarbonate resin of the present invention.

In this photoconductor, light which has passed through the chargetransport layer 4 reaches the charge generation layer 5, and chargecarriers are generated within the charge generation layer 5. The chargecarriers which are necessary for the light decay for latentelectrostatic image formation are generated by the charge generationmaterial 3, and accepted and transported by the charge transport layer4. The generation and transportation of the charge carriers areperformed by the same mechanism as that in the photoconductor shown inFIG. 2.

In this case, the charge transport layer 4 comprises the aromaticpolycarbonate resin, optionally in combination with a binder agent.Furthermore, in order to increase the efficiency of generating thecharge carriers, the charge generation layer 5 may further comprise thearomatic polycarbonate resin of the present invention, and thephotoconductive layer 2b including the charge generation layer 5 and thecharge transport layer 4 may further comprise a low-molecular weightcharge transport material. This can be applied to the embodiments ofFIGS. 4 to 6 to be described later.

In the electrophotographic photoconductor of FIG. 3, a protective layer6 may be provided on the charge transport layer 4 as shown in FIG. 4.The protective layer 6 may comprise the aromatic polycarbonate resin ofthe present invention, optionally in combination with a binder agent. Insuch a case, it is effective that the protective layer 6 be provided ona charge transport layer in which a low-molecular weight chargetransport material is dispersed. The protective layer 6 may be providedon the photoconductive layer 2a of the photoconductor as shown in FIG.2.

Referring to FIG. 5, there is shown still another embodiment of anelectrophotographic photoconductor according to the present invention.In this figure, the overlaying order of the charge generation layer 5and the charge transport layer 4 comprising the aromatic polycarbonateresin is reversed in view of the electrophotographic photoconductor asshown in FIG. 3. The mechanism of the generation and transportation ofcharge carriers is substantially the same as that of the photoconductorshown in FIG. 3.

In the above photoconductor of FIG. 5, a protective layer 6 may beformed on the charge generation layer 5 as shown in FIG. 6 in light ofthe mechanical strength of the photoconductor.

When the electrophotographic photoconductor according to the presentinvention as shown in FIG. 1 is prepared, at least one aromaticpolycarbonate resin of the present invention is dissolved in a solvent,with the addition thereto of a binder agent when necessary. To the thusprepared solution, a sensitizing dye is added, so that a photoconductivelayer coating liquid is prepared. The thus prepared photoconductivelayer coating liquid is coated on an electroconductive support 1 anddried, so that a photoconductive layer 2 is formed on theelectroconductive support 1.

It is preferable that the thickness of the photoconductive layer 2 be inthe range of 3 to 50 μm, more preferably in the range of 5 to 20 μm. Itis preferable that the amount of the aromatic polycarbonate resin of thepresent invention be in the range of 30 to 100 wt. % of the total weightof the photoconductive layer 2.

It is preferable that the amount of the sensitizing dye for use in thephotoconductive layer 2 be in the range of 0.1 to 5 wt. %, morepreferably in the range of 0.5 to 3 wt. % of the total weight of thephotoconductive layer 2.

Specific examples of the sensitizing dye for use in the presentinvention are triarylmethane dyes such as Brilliant Green, Victoria BlueB, Methyl Violet, Crystal Violet and Acid Violet 6B; xanthene dyes suchas Rhodamine B, Rhodamine 6G, Rhodamine G Extra, Eosin S, Erythrosin,Rose Bengale and Fluoresceine; thiazine dyes such as Methylene Blue; andcyanine dyes such as cyanin.

The electrophotographic photoconductor shown in FIG. 2 can be obtainedby the following method:

The finely-divided particles of the charge generation material 3 aredispersed in a solution in which at least one aromatic polycarbonateresin of the present invention, or a mixture of the aromaticpolycarbonate resin and the binder agent is dissolved, so that a coatingliquid for the photoconductive layer 2a is prepared. The coating liquidthus prepared is coated on the electroconductive support 1 and thendried, whereby the photoconductive layer 2a is provided on theelectroconductive support 1.

It is preferable that the thickness of the photoconductive layer 2a bein the range of 3 to 50 μm, more preferably in the range of 5 to 20 μm.It is preferable that the amount of the aromatic polycarbonate resin foruse in the photoconductive layer 2a be in the range of 40 to 100 wt. %of the total weight of the photoconductive layer 2a.

It is preferable that the amount of the charge generation material 3 foruse in the photoconductive layer 2a be in the range of 0.1 to 50 wt. %,more preferably in the range of 1 to 20 wt. % of the total weight of thephotoconductive layer 2a.

Specific examples of the charge generation material 3 for use in thepresent invention are as follows: inorganic materials such as selenium,selenium-tellurium, cadmium sulfide, cadmium sulfide-selenium andα-silicone; and organic pigments such as an azo pigment, for example,C.I. Pigment Blue 25 (C.I. 21180), C.I. Pigment Red 41 (C.I. 21200),C.I. Acid Red 52 (C.I. 45100), C.I. Basic Red 3 (C.I. 45210), an azopigment having a carbazole skeleton (Japanese Laid-Open PatentApplication 53-95033), an azo pigment having a distyryl benzene skeleton(Japanese Laid-Open Patent Application 53-133445), an azo pigment havinga triphenylamine skeleton (Japanese Laid-Open Patent Application53-132347), an azo pigment having a dibenzothiophene skeleton (JapaneseLaid-Open Patent Application 54-21728), an azo pigment having anoxadiazole skeleton (Japanese Laid-Open Patent Application 54-12742), anazo pigment having a fluorenone skeleton (Japanese Laid-Open PatentApplication 54-22834), an azo pigment having a bisstilbene skeleton(Japanese Laid-Open Patent Application 54-17733), an azo pigment havinga distyryl oxadiazole skeleton (Japanese Laid-Open Patent Application54-2129), and an azo pigment having a distyryl carbazole skeleton(Japanese Laid-Open Patent Application 54-14967); a phthalocyaninepigment such as C.I. Pigment Blue 16 (C.I. 74100); an indigo pigmentsuch as C.I. Vat Brown 5 (C.I. 73410) and C.I. Vat Dye (C.I. 73030); anda perylene pigment such as Algol Scarlet B and Indanthrene Scarlet R(made by Bayer Co., Ltd.). These charge generation materials may be usedalone or in combination.

The electrophotographic photoconductor shown in FIG. 3 can be obtainedby the following method:

To provide the charge generation layer 5 on the electroconductivesupport 1, the charge generation material is vacuum-deposited on theelectroconductive support 1. Alternatively, the finely-divided particlesof the charge generation material 3 are dispersed in an appropriatesolvent, together with the binder agent when necessary, so that acoating liquid for the charge generation layer 5 is prepared. The thusprepared coating liquid is coated on the electroconductive support 1 anddried, whereby the charge generation layer 5 is formed on theelectroconductive support 1. The charge generation layer 5 may besubjected to surface treatment by buffing and adjustment of thethickness thereof if required. On the thus formed charge generationlayer 5, a coating liquid in which at least one aromatic polycarbonateresin of the present invention, optionally in combination with a binderagent is dissolved is coated and dried, so that the charge transportlayer 4 is formed on the charge generation layer 5. In the chargegeneration layer 5, the same charge generation materials as employed inthe above-mentioned photoconductive layer 2a can be used.

The thickness of the charge generation layer 5 is 5 μm or less,preferably 2 μm or less. It is preferable that the thickness of thecharge transport layer 4 be in the range of 3 to 50 μm, more preferablyin the range of 5 to 20 μm.

When the charge generation layer 5 is provided on the electroconductivesupport 1 by coating the dispersion in which finely-divided particles ofthe charge generation material 3 are dispersed in an appropriatesolvent, it is preferable that the amount of finely divided particles ofthe charge generation material 3 for use in the charge generation layer5 be in the range of 10 to 100 wt. %, more preferably in the range ofabout 50 to 100 wt. % of the total weight of the charge generation layer5. It is preferable that the amount of the aromatic polycarbonate resinof the present invention for use in the charge transport layer 4 be inthe range of 40 to 100 wt. % of the total weight of the charge transportlayer 4.

The photoconductive layer 2b of the photoconductor shown in FIG. 3 maycomprise a low-molecular-weight charge transporting material aspreviously mentioned.

Examples of the low-molecular-weight charge transporting material foruse in the present invention are as follows: oxazole derivatives,oxadiazole derivatives (Japanese Laid-Open Patent Applications 52-139065and 52-139066), imidazole derivatives, triphenylamine derivatives(Japanese Laid-Open Patent Application 3-285960), benzidine derivatives(Japanese Patent Publication 58-32372), α-phenylstilbene derivatives(Japanese Laid-Open Patent Application 57-73075), hydrazone derivatives(Japanese Laid-Open Patent Applications 55-154955, 55-156954, 55-52063,and 56-81850), triphenylmethane derivatives (Japanese Patent Publication51-10983), anthracene derivatives (Japanese Laid-Open Patent Application51-94829), styryl derivatives (Japanese Laid-Open Patent Applications56-29245 and 58-198043), carbazole derivatives (Japanese Laid-OpenPatent Application 58-58552), and pyrene derivatives (Japanese Laid-OpenPatent Application 2-94812).

To prepare the photoconductor shown in FIG. 4, a coating liquid for theprotective layer 6 is prepared by dissolving the aromatic polycarbonateresin of the present invention, optionally in combination with thebinder agent, in a solvent, and the thus obtained coating liquid iscoated on the charge transport layer 4 of the photoconductor shown inFIG. 3, and dried.

It is preferable that the thickness of the protective layer 6 be in therange of 0.15 to 10 μm. It is preferable that the amount of the aromaticpolycarbonate resin of the present invention for use in the protectivelayer 6 be in the range of 40 to 100 wt. % of the total weight of theprotective layer 6.

The electrophotographic photoconductor shown in FIG. 5 can be obtainedby the following method:

The aromatic polycarbonate resin of the present invention, optionally incombination with the binder agent, is dissolved in a solvent to preparea coating liquid for the charge transport layer 4. The thus preparedcoating liquid is coated on the electroconductive support 1 and dried,whereby the charge transport layer 4 is provided on theelectroconductive support 1. On the thus formed charge transport layer4, a coating liquid prepared by dispersing the finely-divided particlesof the charge generation material 3 in a solvent in which the binderagent may be dissolved when necessary, is coated by spray coating anddried, so that the charge generation layer 5 is provided on the chargetransport layer 4. The amount ratios of the components contained in thecharge generation layer 5 and charge transport layer 4 are the same asthose previously described in FIG. 3.

The electrophotographic photoconductor shown in FIG. 6 can be fabricatedby forming a protective layer 6 on the charge generation layer 5 of thephotoconductor shown in FIG. 5.

To obtain any of the aforementioned photoconductors of the presentinvention, a metallic plate or foil made of aluminum, a plastic film onwhich a metal such as aluminum is deposited, and a sheet of paper whichhas been treated so as to be electroconductive can be employed as theelectroconductive support 1.

Specific examples of the binder agent used in the preparation of thephotoconductor according to the present invention are condensationresins such as polyamide, polyurethane, polyester, epoxy resin,polyketone and polycarbonate; and vinyl polymers such aspolyvinylketone, polystyrene, poly-N-vinylcarbazole and polyacrylamide.All the resins having insulating properties and adhesion properties canbe employed.

Some plasticizers may be added to the above-mentioned binder agents,when necessary. Examples of the plasticizer for use in the presentinvention are halogenated paraffin, dimethylnaphthalene and dibutylphthalate. Further, a variety of additives such as an antioxidant, alight stabilizer, a thermal stabilizer and a lubricant may also becontained in the binder agents when necessary.

Furthermore, in the electrophotographic photoconductor according to thepresent invention, an intermediate layer such as an adhesive layer or abarrier layer may be interposed between the electroconductive supportand the photoconductive layer when necessary. Examples of the materialfor use in the intermediate layer are polyamide, nitrocellulose andaluminum oxide. It is preferable that the thickness of the intermediatelayer be 1 μm or less.

When copying is performed by use of the photoconductor according to thepresent invention, the surface of the photoconductor is uniformlycharged to a predetermined polarity in the dark. The uniformly chargedphotoconductor is exposed to a light image so that a latentelectrostatic image is formed on the surface of the photoconductor. Thethus formed latent electrostatic image is developed to a visible imageby a developer, and the developed image can be transferred to a sheet ofpaper when necessary.

The photosensitivity and the durability of the electrophotographicphotoconductor according to the present invention are remarkablyimproved.

Other features of this invention will become apparent in the course ofthe following description of exemplary embodiments, which are given forillustration of the invention and are not intended to be limitingthereof.

PREPARATION EXAMPLE 1

Preparation of dihydroxyl-group-containing diamine compound No. 1, i.e.N',N"-diphenyl-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4"-diamine!

55.77 g (0.11 mol) of 4-formyl-4'-methoxytriphenylamine represented bythe following formula (1) and 80.08 g (0.264 mol) of a bis(phosphonate)compound represented by the following formula (2) were dissolved in 1000ml of DMF, and the mixture was cooled to 15° C. ##STR25##

To the above prepared solution, 36.96 g (0.33 mol) of potassiumtert-butoxide (t-BuOK) was added over a period of 80 minutes, with thereaction mixture being maintained at a temperature in the range of 15°to 25° C.

After stirring for 3.0 hours, the reaction mixture was poured into 3000ml of water. The separating crystals were removed from the mixture byfiltration, washed with water, and dried under reduced pressure, so thata product was obtained. The thus obtained product was chromatographed ona silica gel column using a developing solvent consisting of toluene andn-hexane at a mixing ratio of 1:1, whereby 83.35 g of a distyrylbenzenecompound represented by formula (3) was obtained in a yield of 91.40%.The above-mentioned distyrylbenzene compound was amorphous. ##STR26##

The results of the elemental analysis of this product are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     86.91         5.73   3.21                                           Calcd.    86.93         5.84   3.38                                           ______________________________________                                    

An infrared spectrum of the distyrylbenzene compound of formula (3),taken by use of a KBr tablet, is shown in FIG. 24.

49.74 g (0.06 mol) of the thus obtained distyrylbenzene compound and 30g (0.36 mol) of sodium thioethoxide were added to 500 ml of dry DMF, andthe above prepared mixture was stirred with the application of heatthereto. The reaction mixture was refluxed for an additional 4.5 hours.Thus, the reaction was terminated. After the reaction mixture wascooled, 30 ml of concentrated hydrochloric acid was added to thereaction mixture. The thus obtained reaction mixture was washed withwater and dried over magnesium sulfate, and then, the solvent wasdistilled away from the reaction mixture. The obtained crude product waschromatographed on a silica gel column using a developing solventconsisting of toluene and ethyl acetate at a mixing ratio of 20:3,whereby 45.62 g of a dihydroxyl-group-containing diamine compound No. 1represented by formula (4) was obtained in a yield of 94.92%. Theabove-mentioned dihydroxyl-group-containing diamine compound wasamorphous.

Dihydroxyl-group-containing diamine compound No. 1! ##STR27##

The results of the elemental analysis of the dihydroxyl-group-containingdiamine compound No. 1 are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     87.03         5.82   3.23                                           Calcd.    86.97         5.54   3.50                                           ______________________________________                                    

An infrared spectrum of this dihydroxyl-group-containing diaminecompound No. 1, i.e.N',N"-diphenyl-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4"-diamine,taken by use of a KBr tablet, is shown in FIG. 25.

PREPARATION EXAMPLE 2

Preparation of dihydroxyl-group-containing diamine compound No. 2!

66.69 g (0.21 mol) of 4-formyl-4'-methoxy-4"-methyl-triphenylaminerepresented by the following formula (5) and 50.66 g (0.1 mol) of abis(phosphonate) compound represented by the following formula (2) weredissolved in 500 ml of DMF. ##STR28##

To the above prepared solution, 29.13 g (0.26 mol) of potassiumtert-butoxide (t-BuOK) was dropwise added.

After stirring for 2 hours, the reaction mixture was poured into 1.5 lof water, and neutralized with acetic acid. The resulting precipitatewas separated from the mixture by filtration, and washed with water, sothat yellow powders were obtained. The thus obtained product waschromatographed on a silica gel column using toluene as a developingsolvent. The thus obtained product was recrystallized from a mixedsolvent consisting of toluene and cyclohexane at a mixing ratio of 1:1,whereby 71.84 g of a distyrylbenzene compound represented by formula (6)was obtained in a yield of 84.01%. The above-mentioned distyrylbenzenecompound was amorphous. ##STR29##

The results of the elemental analysis of the above-mentioneddistyrylbenzene compound are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     87.18         6.25   3.05                                           Calcd.    86.88         6.12   3.27                                           ______________________________________                                    

42.75 g (0.05 mol) of the distyrylbenzene compound represented byformula (6) and 40 g (0.48 mol) of sodium thioethoxide were dissolved in500 ml of dry DMF. Then, the mixture was refluxed for 6 hours in astream of nitrogen.

Thereafter, the reaction mixture was cooled to room temperature, andpoured into iced water, and neutralized with concentrated hydrochloricacid. The resulting precipitate was separated from the mixture byfiltration, and washed with water, and then purified by carrying outchromatographic separation on a column of silica gel using as adeveloping solvent a mixed solvent consisting of toluene and ethylacetate at a mixing ratio of 10:1, whereby 38.07 g of adihydroxyl-group-containing diamine compound No. 2 represented byformula (7) was obtained as a green powder in a yield of 92.07%. Theabove-mentioned dihydroxyl-group-containing diamine compound wasamorphous.

Dihydroxyl-group-containing diamine compound No. 2! ##STR30##

The results of the elemental analysis of the dihydroxyl-group-containingdiamine compound No. 2 are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     86.90         6.00   3.11                                           Calcd.    86.93         5.84   3.38                                           ______________________________________                                    

An infrared spectrum of this hydroxyl-group-containing diamine compoundNo. 2, taken by use of a KBr tablet, is shown in FIG. 26.

PREPARATION EXAMPLE 3

Preparation of dihydroxyl-group-containing diamine compound No. 3!

20.39 g (0.067 mol) of 4-formyl-4'-methoxy-triphenylamine represented bythe following formula (1) and 13.29 g (0.028 mol) of a bis(phosphonate)compound represented by the following formula (8) were dissolved in 300ml of DMF. ##STR31##

To the above prepared solution, 9.43 g (0.084 mol) of potassiumtert-butoxide (t-BuOK) was dropwise added.

After stirring for 3 hours, the reaction mixture was poured into 2.0 lof water, and neutralized with acetic acid. The resulting precipitatewas separated from the mixture by filtration, and washed with water, sothat yellow powders were obtained. The thus obtained product waschromatographed on a silica gel column using as a developing solvent amixed solvent consisting of toluene and n-hexane at a mixing ratio of1:1, whereby 10.52 g of a distyrylbenzene compound represented byformula (9) was obtained in a yield of 50.5%. The above-mentioneddistyrylbenzene compound was amorphous. ##STR32##

The results of the elemental analysis of the above-mentioneddistyrylbenzene compound are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     87.15         6.06   3.32                                           Calcd.    86.86         6.12   3.27                                           ______________________________________                                    

9.68 g (0.011 mol) of the distyrylbenzene compound represented byformula (9) and 10 g (0.12 mol) of sodium thioethoxide were added to 150ml of dry DMF. Then, the mixture was refluxed for 8 hours in a stream ofnitrogen.

Thereafter, the reaction mixture was cooled to room temperature, andpoured into iced water, and neutralized with concentrated hydrochloricacid. The resulting precipitate was separated from the mixture byfiltration, and washed with water, and then purified by carrying outchromatographic separation on a column of silica gel using as adeveloping solvent a mixed solvent consisting of toluene and ethylacetate at a mixing ratio of 10:1, whereby 7.0 g of adihydroxyl-group-containing diamine compound No. 3 represented byformula (10) was obtained as a green powder in a yield of 69.79%. Theabove-mentioned dihydroxyl-group-containing diamine compound wasamorphous.

Dihydroxyl-group-containing diamine compound No. 3! ##STR33##

The results of the elemental analysis of the dihydroxyl-group-containingdiamine compound No. 3 are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     86.97         5.80   3.41                                           Calcd.    86.93         5.84   3.38                                           ______________________________________                                    

An infrared spectrum of this hydroxyl-group-containing diamine compoundNo. 3, taken by use of a KBr tablet, is shown in FIG. 27.

PREPARATION EXAMPLE 4

Preparation of dihydroxyl-group-containing diamine compound No. 4!

69.4 g (0.144 mol) of4-formyl-4'-methoxy-4"-(2,2-diphenylvinyl)triphenylamine represented bythe following formula (11) and 30.4 g (0.06 mol) of a bis(phosphonate)compound represented by the following formula (2) were dissolved in 500ml of DMF. ##STR34##

To the above prepared solution, 24.2 g (0.18 mol) of potassiumtert-butoxide (t-BuOK) was added, with the reaction mixture beingmaintained at a temperature in the range of 15° to 25° C.

After stirring for 3.0 hours, the reaction mixture was poured into 2000ml of water. The resulting layer was extracted with ethyl acetate, andpurified by carrying out chromatographic separation on a column ofsilica gel using a developing solvent consisting of toluene and n-hexaneat a mixing ratio of 1:1, whereby 62.3 g of a distyrylbenzene compoundrepresented by formula (12) was obtained in a yield of 89.9%. Theabove-mentioned distyrylbenzene compound was amorphous. ##STR35##

The results of the elemental analysis of this compound are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     89.45         5.67   2.37                                           Calcd.    89.15         5.78   2.36                                           ______________________________________                                    

An infrared spectrum of the above-mentioned distyrylbenzene compound offormula (12), taken by use of a KBr tablet, is shown in FIG. 28.

57.8 g (0.05 mol) of the distyrylbenzene compound represented by formula(12) and 30 g (0.36 mol) of sodium thioethoxide were added to 500 ml ofdry DMF, and the above prepared mixture was refluxed for 8 hours in astream of nitrogen.

Thereafter, the reaction mixture was cooled to room temperature, andpoured into iced water, and neutralized with concentrated hydrochloricacid. The resulting precipitate was separated from the mixture byfiltration, and washed with water, and then purified by carrying outchromatographic separation on a column of silica gel using as adeveloping solvent a mixed solvent consisting of toluene and ethylacetate at a mixing ratio of 10:1, whereby 52.6 g of adihydroxyl-group-containing diamine compound No. 4 represented byformula (13) was obtained as a yellow powder in a yield of 93.3%. Theabove-mentioned dihydroxyl-group-containing diamine compound wasamorphous.

Dihydroxyl-group-containing diamine compound No. 4! ##STR36##

The results of the elemental analysis of the dihydroxyl-group-containingdiamine compound No. 4 are as follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     89.11         5.49   2.48                                           Calcd.    89.24         5.57   2.42                                           ______________________________________                                    

An infrared spectrum of this hydroxyl-group-containing diamine compoundNo. 4, taken by use of a KBr tablet, is shown in FIG. 29.

EXAMPLE 1--1

Synthesis of aromatic polycarbonate resin No. 1)!

5.92 g (0.00739 mol) ofN',N"-diphenyl-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4"-diamineobtained in Preparation Example 1, represented by formula (4), and 2.12g (0.021 mol) of triethylamine were dissolved in 40 ml of drytetrahydrofuran to prepare a solution (a). A solution (b) prepared bydissolving 1.70 g (0.00735 mol) of diethylene glycol bis(chloroformate)in 8 ml of dry tetrahydrofuran was added dropwise to the solution (a)over a period of 80 minutes under water-cooled condition.

After completion of the addition, the above obtained viscous reactionmixture was stirred for 80 minutes, and then 0.8 g of a drytetrahydrofuran solution containing 4 wt. % of phenol was added to thereaction mixture, followed by stirring for 60 minutes.

Thereafter, the obtained viscous reaction mixture was caused toprecipitate in methanol, and a crude product was separated from thereaction mixture by filtration. The obtained product was purified byrepeating the process of dissolving the product in tetrahydrofuran andprecipitating it in methanol twice. Thereafter, the precipitated productwas filtered off, and dried, so that 5.49 g of an aromatic polycarbonateresin No. 1 according to the present invention having a repeat unit ofthe following formula was obtained in a yield of 81.82%.

Aromatic polycarbonate resin No. 1! ##STR37##

The glass transition temperature (Tg) of the above obtained aromaticpolycarbonate resin No. 1 was 122.5 ° C.

The polystyrene-reduced number-average molecular weight andweight-average molecular weight, which were measured by the gelpermeation chromatography, were respectively 34,000 and 161,300.

The results of the elemental analysis of the thus obtained compound areas follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     79.98         5.17   2.97                                           Calcd.    79.98         5.45   2.91                                           ______________________________________                                    

FIG. 7 shows an infrared spectrum of the aromatic polycarbonate resinNo. 1, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm⁻¹.

EXAMPLE 1-2

Synthesis of aromatic polycarbonate resin No. 2)!

5.92 g (0.00739 mol) ofN',N"-diphenyl-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4"-diamineobtained in Preparation Example 1, represented by formula (4), and 2.12g (0.021 mol) of triethylamine were dissolved in 50 ml of drytetrahydrofuran to prepare a solution (a). A solution (b) prepared bydissolving in 8 ml of dry tetrahydrofuran 2.69 g (0.00735 mol) ofpolytetramethylene ether glycol bis(chloroformate), which was preparedfrom polytetramethylene ether glycol with an average molecular weight of250, was added dropwise to the solution (a) over a period of 80 minutesunder water-cooled condition.

After completion of the addition, the above obtained viscous reactionmixture was stirred for 80 minutes, and then 0.8 g of a drytetrahydrofuran solution containing 4 wt. % of phenol was added to thereaction mixture, followed by stirring for 60 minutes.

Thereafter, the obtained viscous reaction mixture was caused toprecipitate in methanol, and a crude product was separated from thereaction mixture by filtration. The obtained product was purified byrepeating the process of dissolving the product in tetrahydrofuran andprecipitating it in methanol twice. Thereafter, the precipitated productwas filtered off and dried, so that 4.84 g of an aromatic polycarbonateresin No. 2 according to the present invention having a repeat unit ofthe following formula was obtained in a yield of 63.21%.

Aromatic polycarbonate resin No. 2! ##STR38##

The glass transition temperature (Tg) of the above obtained aromaticpolycarbonate resin No. 2 was 86.9° C.

The polystyrene-reduced number-average molecular weight andweight-average molecular weight, which were measured by the gelpermeation chromatography, were respectively 30,417 and 99,227.

The results of the elemental analysis of the thus obtained compound areas follows:

    ______________________________________                                        Elemental analysis:                                                                   % C         % H    % N                                                ______________________________________                                        Found     79.06         6.18   2.58                                           Calcd.    79.31         6.32   2.56                                           ______________________________________                                    

FIG. 8 shows an infrared spectrum of the aromatic polycarbonate resinNo. 2, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm⁻¹.

EXAMPLES 1-3 AND 1-4

Synthesis of aromatic polycarbonate resins Nos. 3 and 4!

The procedure for preparation of the aromatic polycarbonate resin No. 1in Example 1--1 was repeated except that diethylene glycolbis(chloroformate) used in Example 1--1 was replaced by the respectivebis(chloroformate) compounds.

Thus, aromatic polycarbonate resins No. 3 and No. 4 according to thepresent invention were obtained, respectively having repeat units of thefollowing formulae.

Aromatic polycarbonate resin No. 3! ##STR39## Aromatic polycarbonateresin No. 4! ##STR40##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of each of the obtained aromatic polycarbonate resins No. 3 andNo. 4 are shown in Table 1.

FIGS. 9 and 10 respectively show infrared spectra of the aromaticpolycarbonate resins No. 3 and No. 4 obtained in Examples 1-3 and 1-4,taken by use of an NaCl film.

EXAMPLE 1-5

Synthesis of aromatic polycarbonate resin No. 5!

The procedure for preparation of the aromatic polycarbonate resin No. 3in Example 1-3 was repeated except that the dihydroxyl-group-containingdiamine compound No. 1, that is,N',N"-diphenyl-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4"-diamineobtained in Preparation Example 1, represented by formula (4) used inExample 1-3 was replaced by the dihydroxyl-group-containing diaminecompound No. 3 obtained in Preparation Example 3, represented by formula(10): ##STR41##

Thus, 4.63 g of an aromatic polycarbonate resin No. 5 according to thepresent invention having a repeat unit of the following formula wasobtained in a yield of 97.9%.

Aromatic polycarbonate resin No. 5! ##STR42##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 5 are shown inTable 1.

FIG. 11 shows an infrared spectrum of the aromatic polycarbonate resinNo. 5 obtained in Example 1-5, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm⁻¹.

EXAMPLES 1-6 TO 1-8

Synthesis of aromatic polycarbonate resins Nos. 6 to 8!

The procedures for preparation of the aromatic polycarbonate resins No.1 in Example 1-1, No. 2 in Example 1-2, and No. 3 in Example 1-3 wereindependently repeated except that the dihydroxyl-group-containingdiamine compound No. 1, that is,N',N"-diphenyl-N',N"bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4'-diamineobtained in Preparation Example 1, represented by formula (4) wasreplaced by the dihydroxyl-group-containing diamine compound No. 2prepared in Preparation Example 2, represented by the following formula(7): ##STR43##

Thus, aromatic polycarbonate resins Nos. 6 to 8 according to the presentinvention, having the respective repeat units of the following formulae,were obtained.

Aromatic polycarbonate resin No. 6! ##STR44## Aromatic polycarbonateresin No. 7! ##STR45## Aromatic polycarbonate resin No. 8! ##STR46##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of each of the obtained aromatic polycarbonate resins No. 6 toNo. 8 are shown in Table 1.

FIGS. 12 to 14 show infrared spectra of the aromatic polycarbonateresins No. 6 to No. 8 respectively obtained in Examples 1-6 to 1-8,taken by use of an NaCl film.

EXAMPLE 1-9

Synthesis of aromatic polycarbonate resin No. 9!

1.60 g (0.002 mol) ofN',N"-diphenyl-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4"-diamineobtained in Preparation Example 1, represented by formula (4), wasplaced into a reaction vessel. An aqueous solution prepared bydissolving 0.32 g (0.008 mol) of sodium hydroxide in 30 ml ofion-exchange water was added to the above-mentioneddihydroxyl-group-containing diamine compound No. 1, and a mixture thusobtained was stirred. A solution prepared by dissolving 0.356 g (0.0012mol) of triphosgene in 10 ml of methylene chloride was added dropwise tothe above-mentioned mixture over a period of 20 minutes under ice-cooledcondition.

After completion of the addition, 5 ml of methylene chloride was addedto the reaction mixture as rinsing the vessel. Then, 0.1 g (0.025 mol)of sodium hydroxide was added to the reaction mixture at roomtemperature. Further, with the addition of one drop of triethylamine,the reaction mixture was stirred for 2 hours.

Thereafter, the obtained viscous reaction mixture was successivelywashed with a 5% aqueous solution of sodium hydroxide, a 2% aqueoussolution of hydrochloric acid, and ion-exchange water, and caused toprecipitate in methanol. The resultant precipitate was separated fromthe reaction mixture by filtration, and dried, so that 1.25 g of anaromatic polycarbonate resin No. 9 according to the present inventionhaving a repeat unit of the following formula was obtained in a yield of75.3%.

Aromatic polycarbonate resin No. 9! ##STR47##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 9 are shown inTable 1.

FIG. 15 shows an infrared spectrum of the aromatic polycarbonate resinNo. 9 obtained in Example 1-9, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm⁻¹.

EXAMPLE 1-10

Synthesis of aromatic polycarbonate resin No. 10!

The procedure for preparation of the aromatic polycarbonate resin No. 9in Example 1-9 was repeated except that the dihydroxyl-group-containingdiamine compound No. 1, that is,N',N"-diphenyl-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)benzene-4',4"-diamineobtained in Preparation Example 1, represented by formula (4) used inExample 1-9 was replaced by the dihydroxyl-group-containing diaminecompound No. 3 represented by formula (10): ##STR48##

Thus, 0.91 g of an aromatic polycarbonate resin No. 10 according to thepresent invention having a repeat unit of the following formula wasobtained in a yield of 53.2%.

Aromatic polycarbonate resin No. 10! ##STR49##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 10 are shownin Table 1.

FIG. 16 shows an infrared spectrum of the aromatic polycarbonate resinNo. 10 obtained in Example 1-10, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm⁻¹.

EXAMPLE 1-11

Synthesis of aromatic polycarbonate resin No. 11!

5.14 g (0.006 mol) of the dihydroxyl-group-containing diamine compoundNo. 2 prepared in Preparation Example 2, that is,N',N"-bis(4-methylphenyl)-N',N"-bis(4-hydroxyphenyl)-1,4-bis(α-phenylstyryl)-benzene-4',4"-diamine,represented by formula (7), and 1.54 g (0.006 mol) of bisphenol C wereplaced into a reaction vessel. An aqueous solution prepared bydissolving 1.92 g (0.048 mol) of sodium hydroxide in 800 ml ofion-exchange water was added to the above-mentioned mixture, followed bystirring. A solution prepared by dissolving 2.14 g (0.0012 mol) oftriphosgene in 500 ml of methylene chloride was added dropwise to theabove-mentioned mixture over a period of 60 minutes under ice-cooledcondition.

After completion of the addition, 100 ml of methylene chloride was addedto the reaction mixture as rinsing the vessel. Then, 0.6 g of sodiumhydroxide was added to the reaction mixture at room temperature.Further, with the addition of one drop of triethylamine, the reactionmixture was stirred for 5 hours.

Thereafter, the obtained viscous reaction mixture was successivelywashed with a 5% aqueous solution of sodium hydroxide, a 2% aqueoussolution of hydrochloric acid, and ion-exchange water, and caused toprecipitate in methanol. The resultant precipitate was separated fromthe reaction mixture by filtration and dried, so that 5.11 g of anaromatic polycarbonate resin No. 11 according to the present inventionhaving a repeat unit of the following formula was obtained in a yield of73.1%.

Aromatic polycarbonate resin No. 11! ##STR50##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 11 are shownin Table 1.

FIG. 17 shows an infrared spectrum of the aromatic polycarbonate resinNo. 11 obtained in Example 1-11, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm³¹ 1.

EXAMPLE 1-12

Synthesis of aromatic polycarbonate resin No. 12!

5.64 g (0.005 mol) of the dihydroxyl-group-containing diamine compoundNo. 4 obtained in Preparation Example 4, represented by formula (13),and 1.52 g (0.015 mol) of triethylamine were dissolved in 40 ml of drytetrahydrofuran, so that a solution (a) was prepared. A solution (b)prepared by dissolving 1.21 g (0.005 mol) of diethylene glycolbis(chloroformate) in 10 ml of dry tetrahydrofuran was added dropwise tothe solution (a) over a period of 30 minutes under water-cooledcondition.

After completion of the addition, the resultant viscous reaction mixturewas stirred for 120 minutes, and 0.8 g of a dry tetrahydrofuran solutionof 4 wt. % of phenol was added to the reaction mixture.

After stirring for 120 minutes, the obtained viscous reaction mixturewas successively washed with a 5% aqueous solution of sodium hydroxide,a 2% aqueous solution of hydrochloric acid, and ion-exchange water, andcaused to precipitate in methanol. The resultant precipitate wasseparated from the reaction mixture by filtration and dried, so that5.83 g of an aromatic polycarbonate resin No. 12 according to thepresent invention having a repeat unit of the following formula wasobtained in a yield of 88.6%.

Aromatic polycarbonate resin No. 12! ##STR51##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 12 are shownin Table 1.

FIG. 18 shows an infrared spectrum of the aromatic polycarbonate resinNo. 12 obtained in Example 1-12, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm⁻¹.

EXAMPLES 1-13 AND 1-14

Synthesis of aromatic polycarbonate resins No. 13 and No. 14!

The procedure for preparation of the aromatic polycarbonate resin No. 12in Example 1-12 was repeated except that diethylene glycolbis(chloroformate) used in Example 1-12 was replaced by the respectivebis(chloroformate) compounds.

Thus, aromatic polycarbonate resins No. 13 and No. 14 according to thepresent invention were obtained, respectively having repeat units of thefollowing formulae.

Aromatic polycarbonate resin No. 13! ##STR52## Aromatic polycarbonateresin No. 14! ##STR53##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of each of the obtained aromatic polycarbonate resins No. 13and No. 14 are shown in Table 1.

FIGS. 19 and 20 respectively show infrared spectra of the aromaticpolycarbonate resins No. 13 and No. 14 obtained in Examples 1-13 and1-14, taken by use of an NaCl film.

Each IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1760cm⁻¹.

EXAMPLE 1-15

Synthesis of aromatic polycarbonate resin No. 15!

2.25 g (0.002 mol) of the dihydroxyl-group-containing diamine compoundNo. 4 obtained in Preparation Example 4, represented by formula (13),was placed into a reaction vessel. An aqueous solution prepared bydissolving 0.32 g (0.008 mol) of sodium hydroxide in 30 ml ofion-exchange water was added to the above-mentioneddihydroxyl-group-containing diamine compound No. 4, and a mixture thusobtained was stirred. A solution prepared by dissolving 0.356 g (0.0012mol) of triphosgene in 10 ml of methylene chloride was added dropwise tothe above-mentioned mixture over a period of 20 minutes under ice-cooledcondition.

After completion of the addition, 5 ml of methylene chloride was addedto the reaction mixture as rinsing the vessel. Then, 0.1 g (0.025 mol)of sodium hydroxide was added to the reaction mixture at roomtemperature. Further, with the addition of one drop of triethylamine,the reaction mixture was stirred for 2 hours.

Thereafter, the obtained viscous reaction mixture was successivelywashed with a 5% aqueous solution of sodium hydroxide, a 2% aqueoussolution of hydrochloric acid, and ion-exchange water, and caused toprecipitate in methanol. The resultant precipitate was separated fromthe reaction mixture by filtration and dried, so that 1.25 g of anaromatic polycarbonate resin No. 15 according to the present inventionhaving a repeat unit of the following formula was obtained in a yield of52.7%.

Aromatic polycarbonate resin No. 15! ##STR54##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 15 are shownin Table 1.

FIG. 21 shows an infrared spectrum of the aromatic polycarbonate resinNo. 15 obtained in Example 1-15, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1775cm⁻¹.

EXAMPLE 1-16

Synthesis of aromatic polycarbonate resin No. 16!

5.07 g (0.0045 mol) of the dihydroxyl-group-containing diamine compoundNo. 4 obtained in Preparation Example 4, represented by formula (13),and 1.02 g (0.0045 mol) of bisphenol A were placed into a reactionvessel. An aqueous solution prepared by dissolving 0.72 g (0.018 mol) ofsodium hydroxide in 60 ml of ion-exchange water was added to theabove-mentioned mixture, followed by stirring. Further, 20 ml ofmethylene chloride was added to the mixture. A solution prepared bydissolving 0.80 g (0.0027 mol) of triphosgene in 15 ml of methylenechloride was added dropwise to the above-mentioned mixture over a periodof 60 minutes under ice-cooled condition.

After completion of the addition, 5 ml of methylene chloride was addedto the reaction mixture as rinsing the vessel. Then, 0.225 g of sodiumhydroxide was added to the reaction mixture at room temperature.Further, with the addition of one drop of triethylamine, the reactionmixture was stirred for 5 hours. Then, the reaction mixture was furtherstirred for one hour with the addition thereto of 60 mg oftert-butylphenol.

Thereafter, the obtained viscous reaction mixture was successivelywashed with a 5% aqueous solution of sodium hydroxide, a 2% aqueoussolution of hydrochloric acid, and ion-exchange water, and caused toprecipitate in methanol. The resultant precipitate was separated fromthe reaction mixture by filtration and dried, so that 5.73 g of anaromatic polycarbonate resin No. 16 according to the present inventionhaving a repeat unit of the following formula was obtained in a yield of88.6%.

Aromatic polycarbonate resin No. 16! ##STR55##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 16 are shownin Table 1.

FIG. 22 shows an infrared spectrum of the aromatic polycarbonate resinNo. 16 obtained in Example 1-16, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1775cm⁻¹.

EXAMPLE 1-17

Synthesis of aromatic polycarbonate resin No. 17!

The procedure for preparation of the aromatic polycarbonate resin No. 16in Example 1-16 was repeated except that bisphenol A used in Example1-16 was replaced by bisphenol Z.

Thus, an aromatic polycarbonate resin No. 17 according to the presentinvention having a repeat unit of formula was obtained.

Aromatic polycarbonate resin No. 17! ##STR56##

The glass transition temperature (Tg), the polystyrene-reducednumber-average molecular weight (Mn), the polystyrene-reducedweight-average molecular weight (Mw), and the results of the elementalanalysis of the obtained aromatic polycarbonate resin No. 17 are shownin Table 1.

FIG. 23 shows an infrared spectrum of the aromatic polycarbonate resinNo. 17 obtained in Examples 1-17, taken by use of an NaCl film.

The IR spectrum indicates the appearance of the characteristicabsorption peak due to C═O stretching vibration of carbonate at 1775cm⁻¹.

                                      TABLE 1                                     __________________________________________________________________________                          Elemental Analysis                                      Example No.                                                                         Tg (°C.)                                                                     Molecular Weight (*) MnMw                                                                ##STR57##                                                                            ##STR58##                                                                           ##STR59##                                 __________________________________________________________________________    1-1   122.5 34000                                                                              161300                                                                              ##STR60##                                                                            ##STR61##                                                                           ##STR62##                                 1-2    86.9 30417                                                                               99227                                                                              ##STR63##                                                                            ##STR64##                                                                           ##STR65##                                 1-3   127.3 31797                                                                              134725                                                                              ##STR66##                                                                            ##STR67##                                                                           ##STR68##                                 1-4   177.6 11828                                                                               32723                                                                              ##STR69##                                                                            ##STR70##                                                                           ##STR71##                                 1-5   149.1 18200                                                                              139000                                                                              ##STR72##                                                                            ##STR73##                                                                           ##STR74##                                 1-6   147.7 19200                                                                              156000                                                                              ##STR75##                                                                            ##STR76##                                                                           ##STR77##                                 1-7   100.7 13300                                                                               76500                                                                              ##STR78##                                                                            ##STR79##                                                                           ##STR80##                                 1-8   149.1 18200                                                                              194000                                                                              ##STR81##                                                                            ##STR82##                                                                           ##STR83##                                 1-9   201.5 23300                                                                              183000                                                                              ##STR84##                                                                            ##STR85##                                                                           ##STR86##                                  1-10 198.0  5000                                                                               26900                                                                              ##STR87##                                                                            ##STR88##                                                                           ##STR89##                                  1-11 182.6 15300                                                                              225000                                                                              ##STR90##                                                                            ##STR91##                                                                           ##STR92##                                  1-12 150.0 18700                                                                              128000                                                                              ##STR93##                                                                            ##STR94##                                                                           ##STR95##                                  1-13 116.8 12600                                                                               64800                                                                              ##STR96##                                                                            ##STR97##                                                                           ##STR98##                                  1-14 145.5 11700                                                                               89700                                                                              ##STR99##                                                                            ##STR100##                                                                          ##STR101##                                 1-15 192.8 18100                                                                              158000                                                                              ##STR102##                                                                           ##STR103##                                                                          ##STR104##                                 1-16 185.3 18900                                                                               79000                                                                              ##STR105##                                                                           ##STR106##                                                                          ##STR107##                                 1-17 190.0 11600                                                                              65600                                                                               ##STR108##                                                                           ##STR109##                                                                          ##STR110##                                __________________________________________________________________________     (*) The molecular weight is expressed by a polystyrenereduced value.     

EXAMPLE 2-1

Fabrication of Photoconductor No. 1!

(Formation of intermediate layer)

A commercially available polyamide resin (Trademark "CM-8000", made byToray Industries, Inc.) was dissolved in a mixed solvent of methanol andbutanol, so that a coating liquid for an intermediate layer wasprepared.

The thus prepared coating liquid was coated on an aluminum plate by adoctor blade, and dried at room temperature, so that an intermediatelayer with a thickness of 0.3 μm was provided on the aluminum plate.(Formation of charge generation layer)

A coating liquid for a charge generation layer was prepared bydispersing a bisazo compound of the following formula, serving as acharge generation material, in a mixed solvent of cyclohexanone andmethyl ethyl ketone in a ball mill. The thus obtained coating liquid wascoated on the above prepared intermediate layer by a doctor blade, anddried at room temperature. Thus, a charge generation layer with athickness of about 1 μm was formed on the intermediate layer. (Bisazocompound) ##STR111## Formation of charge transport layer!

The aromatic polycarbonate resin No. 1 of the present invention preparedin Example 1--1, serving as a charge transport material, was dissolvedin dichloromethane. The thus obtained coating liquid was coated on theabove prepared charge generation layer by a doctor blade, and dried atroom temperature and then at 120° C. for 20 minutes, so that a chargetransport layer with a thickness of about 20 μm was provided on thecharge generation layer.

Thus, an electrophotographic photoconductor No. 1 according to thepresent invention was fabricated.

EXAMPLES 2-2 TO 2-15

The procedure for fabrication of the electrophotographic photoconductorNo. 1 in Example 2-1 was repeated except that the aromatic polycarbonateresin No. 1 for use in the charge transport layer coating liquid inExample 2-1 was replaced by each of the aromatic polycarbonate resins(as illustrated in Table 2).

Thus, electrophotographic photoconductors No. 2 to No. 15 according tothe present invention were fabricated.

Each of the electrophotographic photoconductors No. 1 through No. 15according to the present invention obtained in Examples 2-1 to 2-15 wascharged negatively in the dark under application of -6 kV of coronacharge for 20 seconds, using a commercially available electrostaticcopying sheet testing apparatus ("Paper Analyzer Model SP-428" made byKawaguchi Electro Works Co., Ltd.). Then, each electrophotographicphotoconductor was allowed to stand in the dark for 20 seconds withoutapplying any charge thereto, and the surface potential Vo (V) of thephotoconductor was measured. Each photoconductor was then illuminated bya tungsten lamp in such a manner that the illuminance on the illuminatedsurface of the photoconductor was 4.5 lux, and the exposure E_(1/2)(lux·sec) required to reduce the initial surface potential Vo (V) to 1/2the initial surface potential Vo (V) was measured. The results are shownin Table 2.

                  TABLE 2                                                         ______________________________________                                        Example  Aromatic Polycarbonate                                                                         -Vo    E.sub.1/2                                    No.      Resin No.        (V)    (lux · sec)                         ______________________________________                                        1        No. 1            1291   1.15                                         2        No. 2            1087   0.92                                         3        No. 3            1325   1.07                                         4        No. 4            1208   1.54                                         5        No. 5             978   0.93                                         6        No. 6            1003   1.01                                         7        No. 7             883   0.94                                         8        No. 8             897   0.85                                         9         No. 12           986   0.93                                         10        No. 13          1021   0.94                                         11        No. 14          1227   0.97                                         12        No. 15           537   1.60                                         13        No. 11           742   1.17                                         14        No. 16           588   1.24                                         15        No. 17           702   1.58                                         ______________________________________                                    

Furthermore, each of the above obtained electrophotographicphotoconductors No. 1 to No. 15 was set in a commercially availableelectrophotographic copying machine, and the photoconductor was chargedand exposed to light images via the original images to form latentelectrostatic images thereon. Then, the latent electrostatic imagesformed on the photoconductor were developed into visible toner images bya dry developer, and the visible toner images were transferred to asheet of plain paper and fixed thereon. As a result, clear toner imageswere obtained on the paper. When a wet developer was employed for theimage formation, clear images were formed on the paper similarly.

As previously explained, the polycarbonate resin for use in thephotoconductive layer of the electrophotographic photoconductoraccording to the present invention comprises a repeat unit of formula(I); or repeat units of formulae (II) and (III). Any of theabove-mentioned aromatic polycarbonate resins have the chargetransporting properties and high mechanical strength, so that thephotosensitivity and durability of the photoconductor are sufficientlyhigh.

Japanese Patent Application No. 7-327364 filed Dec. 15, 1995, JapanesePatent Application No. 8-010228 filed Jan. 24, 1996 and Japanese PatentApplication No. 8-010894 filed Jan. 25, 1996 are hereby incorporated byreference.

What is claimed is:
 1. An electrophotographic photoconductor comprisingan electroconductive support, and a photoconductive layer formed thereoncomprising as an effective component an aromatic polycarbonate resinhaving a repeat unit of formula (I): ##STR112## wherein n is an integerof 5 to 5000; Ar¹ and Ar⁵ may be the same or different, and are eachindependently a bivalent aromatic hydrocarbon group which may have asubstituent or a bivalent heterocyclic group which may have asubstituent; Ar², Ar³, Ar⁴ and Ar⁶ each may be the same or different,and are each independently an aromatic hydrocarbon group which may havea substituent, or a heterocyclic group which may have a substituent; andX is a bivalent aliphatic group, a bivalent cyclic aliphatic group, or##STR113## in which R¹ and R² are each independently an alkyl groupwhich may have a substituent, an aromatic hydrocarbon group which mayhave a substituent, or a halogen atom; l and m are each independently aninteger of 0 to 4; and p is an integer of 0 or 1, and when p=1, Y is astraight-chain, branched or cyclic alkylene group having 1 to 12 carbonatoms, --O--, --S--, --SO--, --SO₂ --, ##STR114## in which Z is abivalent aliphatic hydrocarbon group; a is an integer of 0 to 20; b isan integer of 1 to 2000; and R³ and R⁴ are each independently an alkylgroup which may have a substituent or an aromatic hydrocarbon groupwhich may have a substituent and wherein said photoconductive layerfurther comprises a sensitizing dye or a charge generation material. 2.The electrophotographic photoconductor as claimed in claim 1, whereinsaid aromatic hydrocarbon group represented by Ar¹ and Ar⁵ is phenylenegroup.
 3. The electrophotographic photoconductor as claimed in claim 2,wherein said aromatic hydrocarbon group represented by Ar³ is ##STR115##and said aromatic hydrocarbon group represented by Ar⁴ is ##STR116##wherein R⁵ and R⁶ are each independently an alkyl group which may have asubstituent, an aromatic hydrocarbon group which may have a substituent,or a halogen atom; and r and s are each independently an integer of 0 to4.
 4. An electrophotographic photoconductor comprising anelectroconductive support, and a photoconductive layer formed thereoncomprising as an effective component an aromatic polycarbonate resinhaving a repeat unit of formula (II) and a great unit of formula (III),with the composition ratio of the repeat unit of formula (II) to therepeat unit of formula (III) being in the relationship of 0<k/(k+j)≦1:##STR117## wherein k is an integer of 5 to 5000; j is an integer of 0 to5000; Ar¹ and Ar⁵ may be the same or different, and are eachindependently a bivalent aromatic hydrocarbon group which may have asubstituent or a bivalent heterocyclic group which may have asubstituent; Ar², Ar³, Ar⁴ and Ar⁶ each may be the same or different,and are each independently an aromatic hydrocarbon group which may havea substituent, or a heterocyclic group which may have a substituent; andX is a bivalent aliphatic group, a bivalent cyclic aliphatic group or##STR118## in which R¹ and R² are each independently an alkyl groupwhich may have a substituent, an aromatic hydrocarbon group which mayhave a substituent, or a halogen atom; l and m are each independently aninteger of 0 to 4; and p is an integer of 0 to 1, and when p=1, Y is astraight-chain, branched or cyclic alkylene group having 1 to 12 carbonatoms, --O--, --S--, --SO--, --SO₂ -- ##STR119## in which Z is abivalent aliphatic hydrocarbon group; a is an integer of 0 to 20; b isan integer of 1 to 2000; and R³ and R⁴ are each independently an alkylgroup which may have a substituent or an aromatic hydrocarbon groupwhich may have a substituent and wherein said photoconductive layerfurther comprises a sensitizing dye or a charge generation material. 5.The electrophotographic photoconductor as claimed in claim 4, whereinsaid aromatic hydrocarbon group represented by Ar¹ and Ar⁵ is phenylenegroup.
 6. The electrophotographic photoconductor as claimed in claim 5,wherein said aromatic hydrocarbon group represented by Ar³ is ##STR120##and said aromatic hydrocarbon group represented by Ar⁴ is ##STR121##wherein R⁵ and R⁶ are each independently an alkyl group which may have asubstituent, an aromatic hydrocarbon group which may have a substituent,or a halogen atom; and r and s are each independently an integer of 0 to4.
 7. The electrophotographic photoconductor as claimed in claim 1,wherein said bivalent aromatic hydrocarbon group represented by Ar¹ andAr⁵ is a bivalent group derived from one aromatic hydrocarbon groupselected from the group consisting of benzene, naphthalene, biphenyl,terphenyl, pyrene, fluorene, and 9,9-dimethylfluorene.
 8. Theelectrophotographic photoconductor as claimed in claim 1, wherein saidbivalent heterocyclic group represented by Ar¹ and Ar⁵ is a bivalentgroup derived from one heterocyclic group selected from the groupconsisting of thiophene, benzothiophene, furan, benzofuran andcarbazole.
 9. The electrophotographic photoconductor as claimed in claim1, wherein said bivalent heterocyclic group represented by Ar¹ and Ar⁵is diphenyl ether group in which two aryl groups are bonded via oxygen,or diphenyl thioether group in which two aryl groups are bonded viasulfur.
 10. The electrophotographic photoconductor as claimed in claim1, wherein said substituent for said bivalent aromatic hydrocarbon groupand said bivalent heterocyclic group represented by Ar¹ and Ar⁵ isselected from the group consisting of a halogen atom, an alkyl grouphaving 1 to 12 carbon atom, and an alkoxyl group having 1 to 12 carbonatoms.
 11. The electrophotographic photoconductor as claimed in claim 1,wherein said aromatic hydrocarbon group represented by Ar², Ar³, Ar⁴ andAr⁶ is an aromatic hydrocarbon group selected from the group consistingof phenyl group, naphthyl group, biphenylyl group, terphenylyl group,pyrenyl group, fluorenyl group, 9,9-dimethyl-2-fluorenyl group, and5H-dibenzocycloheptenyl group.
 12. The electrophotographicphotoconductor as claimed in claim 1, wherein said heterocyclic grouprepresented by Ar², Ar³, Ar⁴ and Ar⁶ is a heterocyclic group selectedfrom the group consisting of thienyl group, benzothienyl group, furylgroup, benzofuranyl group and carbazolyl group.
 13. Theelectrophotographic photoconductor as claimed in claim 1, wherein saidsubstituent for said aromatic hydrocarbon group and said heterocyclicgroup represented by Ar², Ar³, Ar⁴ and Ar⁶ is selected from the groupconsisting of a halogen atom, an alkyl group having 1 to 12 carbon atom,and an alkoxyl group having 1 to 12 carbon atoms.
 14. Theelectrophotographic photoconductor as claimed in claim 1, wherein saidaromatic hydrocarbon group represented by R¹ to R⁴ is selected from thegroup consisting of phenyl group which may have a substituent, andbiphenylyl group which may have a substituent.
 15. Theelectrophotographic photoconductor as claimed in claim 3, wherein saidaromatic hydrocarbon group represented by R⁵ and R⁶ is selected from thegroup consisting of phenyl group which may have a substituent, andbiphenylyl group which may have a substituent.
 16. Theelectrophotographic photoconductor as claimed in claim 1, wherein saidalkyl group represented by R¹ to R⁴ has 1 to 12 carbon atoms.
 17. Theelectrophotographic photoconductor as claimed in claim 3, wherein saidalkyl group represented by R⁵ and R⁶ has 1 to 12 carbon atoms.
 18. Theelectrophotographic photoconductor as claimed in claim 4, wherein saidbivalent aromatic hydrocarbon group represented by Ar¹ and Ar⁵ is abivalent group derived from one aromatic hydrocarbon group selected fromthe group consisting of benzene, naphthalene, biphenyl, terphenyl,pyrene, fluorene, and 9,9-dimethylfluorene.
 19. The electrophotographicphotoconductor as claimed in claim 4, wherein said bivalent heterocyclicgroup represented by Ar¹ and Ar⁵ is a bivalent group derived from oneheterocyclic group selected from the group consisting of thiophene,benzothiophene, furan, benzofuran and carbazole.
 20. Theelectrophotographic photoconductor as claimed in claim 4, wherein saidbivalent heterocyclic group represented by Ar¹ and Ar⁵ is diphenyl ethergroup in which two aryl groups are bonded via oxygen, or diphenylthioether group in which two aryl groups are bonded via sulfur.
 21. Theelectrophotographic photoconductor as claimed in claim 4, wherein saidsubstituent for said bivalent aromatic hydrocarbon group and saidbivalent heterocyclic group represented by Ar¹ and Ar⁵ is selected fromthe group consisting of a halogen atom, an alkyl group having 1 to 12carbon atom, and an alkoxyl group having 1 to 12 carbon atoms.
 22. Theelectrophotographic photoconductor as claimed in claim 4, wherein saidaromatic hydrocarbon group represented by Ar², Ar³, Ar⁴ and Ar⁶ is anaromatic hydrocarbon group selected from the group consisting of phenylgroup, naphthyl group, biphenylyl group, terphenylyl group, pyrenylgroup, fluorenyl group, 9,9-dimethyl-2-fluorenyl group, and5H-dibenzocycloheptenyl group.
 23. The electrophotographicphotoconductor as claimed in claim 4, wherein said heterocyclic grouprepresented by Ar², Ar³, Ar⁴ and Ar⁶ is a heterocyclic group selectedfrom the group consisting of thienyl group, benzothienyl group, furylgroup, benzofuranyl group and carbazolyl group.
 24. Theelectrophotographic photoconductor as claimed in claim 4, wherein saidsubstituent for said aromatic hydrocarbon group and said heterocyclicgroup represented by Ar², Ar³, Ar⁴ and Ar⁶ is selected from the groupconsisting of a halogen atom, an alkyl group having 1 to 12 carbon atom,and an alkoxyl group having 1 to 12 carbon atoms.
 25. Theelectrophotographic photoconductor as claimed in claim 4, wherein saidaromatic hydrocarbon group represented by R¹ to R⁴ is selected from thegroup consisting of phenyl group which may have a substituent, andbiphenylyl group which may have a substituent.
 26. Theelectrophotographic photoconductor as claimed in claim 6, wherein saidaromatic hydrocarbon group represented by R⁵ and R⁶ is selected from thegroup consisting of phenyl group which may have a substituent, andbiphenylyl group which may have a substituent.
 27. Theelectrophotographic photoconductor as claimed in claim 4, wherein saidalkyl group represented by R¹ to R⁴ has 1 to 12 carbon atoms.
 28. Theelectrophotographic photoconductor as claimed in claim 6, wherein saidalkyl group represented by R⁵ and R⁶ has 1 to 12 carbons atoms.